One hospital’s story: Ins and outs of low titer O whole blood use in trauma

And then there is the titer.

AABB standard 5.27.1.1 says if LTOWB is used, the blood bank/transfusion service should define low titer and have policies, processes, and procedures for LTOWB use, the maximum volume/units allowed per event, and patient monitoring for adverse effects. “There’s no official definition of low titer,” Dr. Karp said. “You get to define it.”

They defined theirs as negative at a titer of 200 for anti-A and anti-B, which was in line with practice at other institutions and suppliers (per presentations at the 2018 AABB meeting), she said, and allows for a maximum number of donors to be included in collections. They performed a validation of 24 type O donors from their center, using titers of 200 and 50. At 200, only one donor of 24 would have missed the titer; at 50, five of 24 would have missed the titer.

LTOWB would be used only in “adult” patients defined as age 14 or older, which was consistent with how the hospital defines pediatric (under age 14). A maximum of four units of LTOWB would be transfused per patient/event, primarily because of hemolysis concerns but also logistics, Dr. Karp said. “We were not planning to have that much low titer whole blood in-house or in that trauma refrigerator.”

“We were looking at it as a bridge, to be used in those first 10 to 15 minutes while the blood bank is getting coolers of components ready,” she said.

Unused LTOWB would be manufactured into RBC units at shelf life day 14. They discussed whether to discard the unit but decided against it because they have the capability to manufacture. Accompanying plasma would be discarded.

In early 2019 the secured refrigerator “walked in the door,” Dr. Karp said—about 18 months after discussions got underway—at which point refrigerator validation and blood bank/trauma staff education began. LTOWB was built into the EMR, product codes were built, and the titer was validated. They went live on April 1 with four units of O positive LTOWB, two units of O negative LTOWB, and six units of RBCs in the new refrigerator.

“We had an intense period of on-the-spot education and debriefing after each use of low titer O whole blood early on, and then eventually it became more by the book,” she said. One year later, in the middle of the pandemic’s first year, they decided to stop making O negative LTOWB. “We weren’t using it very much, for better or worse.” Few of the trauma patients are female and even fewer are of childbearing potential. “It was decided that if a woman of childbearing potential came in, we would offer them O negative red cells.”

As the blood banker, Dr. Karp explained to the trauma surgeons that the risk of giving O positive low titer O whole blood to a female of childbearing potential was a reasonable risk given that the patient is very ill and thinking not about the baby she might have but about going home. “Many institutions that did make O negative low titer O whole blood had abandoned it,” she said, so the plan to discontinue wasn’t an uncommon one. “O negative red cells are scarce, and we want to make sure they’re going exactly where they need to be and not just sitting in a refrigerator.”

Fig. 1 shows the number of units procured, spun down, transfused, and discarded for a period of just over two years. Beginning in April 2020, she said, “it almost looks like someone turned down the volume on the bars.”

Overall, she said, “we spin down a lot but don’t use very much.” They’ve transfused about 31 percent of what was made available as LTOWB, and discarded two percent. Sixty-six percent of units are spun down to RBCs.

LTOWB manufacture and use will mean ongoing education of the trauma and blood bank staff, she said, whether it’s new employees or those who might need a refresher. Or it could be unique events that call for taking a step back and asking, What did we do here and could we have done it better?

“We’ll be continuing to talk about low titer O whole blood for a long time,” she said.

Sherrie Rice is editor of CAP TODAY.